Effect of Soil Washing with an Amino-Acid-Derived Ionic Liquid on the Properties of Cd-Contaminated Paddy Soil

To reduce contamination levels in Cd-contaminated paddy soil while retaining soil characteristics, we have studied the Cd-removing ability of 15 different amino acid-based ionic liquids, which are considered to be green solvents, as soil washing agents and their impact on soil. The results indicated that the glycine hydrochloride ([Gly][Cl]) removed the most Cd, and under optimized conditions could remove 82.2% of the total Cd. Encouragingly, the morphology of the soil had not been significantly changed by the washing process. After the soil was rinsed twice with water and the pH was adjusted to 6.2 by adding Ca(OH)(2), the germination index of the rice increased by 7.5%. The growth of the rice was also stimulated, with lengths and weights of the rice plants increasing by 56% and 32%, respectively, after two weeks. These experiments demonstrate that amino-acid-derived ionic liquids can be promising soil-washing agents of Cd-contaminated paddy soil.

Automated summary

The Cd-removing ability of 15 different amino acid-based ionic liquids as soil washing agents was studied, and the glycine hydrochloride ([Gly][Cl]) was found to be the most effective in removing Cd. The washing process did not significantly alter the morphology of the soil. After rinsing the soil with water and adjusting the pH, the germination index and growth of rice plants increased significantly. These experiments demonstrate the potential of amino acid-derived ionic liquids as promising soil-washing agents for Cd-contaminated paddy soil.